1. Field of the Invention
This invention relates to a biodegradable biocompostable biodigestible plastic and a process for preparation thereof.
2. The Related Arts
Plastics are manufactured from petroleum namely polyethylene's, polypropylenes, which takes several years to degrade in the environment and therefore pollute water, soil and air.
Environmental degradation of synthetic polymers occurs at varying rates and to varying degrees depending on the characteristics of polymer and its environment. Such degradations are catalyzed by light, heat, air, water, microorganisms, and mechanical forces such as wind, rain, vehicular traffic, etc. Enhancing the stability and/or the degradability of polymers is generally accomplished by additives, changing the polymer backbone, introduction of functional groups, or by blending with appropriate fillers to make the polymer/plastic material from hydrophobic to hydrophilic material. However, many of these techniques for degradation also result in detrimental properties for the polymer products.
Petroleum based synthetic polymers/plastics to overcome the problems and limit of natural material owing to its excellent physical properties, light weight and cost effectiveness, plasticity is one of the modern scientific characteristics established by developing various hydrophilic polymers, especially hydrophilic plastic. However, each country in the present world is preparing for diversified counter measures as pollution problems from numerous plastic products are globally getting serious and it becomes a challenging matter to solve such pollution problems arising out of plastic wastes.
Recycling, incineration and landfill have been mainly used to solve these environmental pollution problems caused by various solid wastes, including plastic. However, disposal of wastes through landfill as well as recycling cannot solve the environmental pollution problems completely owning to its inherent problems.
Accordingly, great interest and studies on development of biodegradable and/or biocompostable plastic which can degrade itself at the life cycle end are increasing recently. The technology on degradable plastic is divided into photodegradable, oxo-degradable, oxo-biodegradable, biodegradable, bio-photodegradable and a combination of photo- and/or oxo and/or biodegradable plastic formulation technologies which are increasing recently on the industrial scale of manufacturing.
While there are many kinds of biodegradable plastic, for example microorganism producing polymers like PHB (poly-β-hydroxybutylate), polymers using microorganism producing biochemical, or polymers having natural polymer like chitin or starch. The problems which are concerned with the present technology about polymers having various additives such as starch have been mentioned and improvements are described in the literature.
U.S. Pat. No. 4,021,388 by G. J. L. Griffin is directed to a process for preparing biodegradable film improved by treating the surface of starch with silane coupling agent to be hydrophobic, but it only increases physical interacting strength a little between matrix resin and starch. However, it has difficulty to solve the problem of degradation in the physical properties of films upon incorporating starch.
While U.S. Pat. Nos. 4,133,784 and 4,337,181 filed by F. H. Otey et. al. of USDA disclose processes for preparing biodegradable films by adding α-starch to ethylene-acrylic copolymer. It has difficulty to generalize for the high price of ethylene-acrylic copolymer and lowering of physical properties of the produced films.
Korean Patent Publication No. 90-006336 and 91-008553 filed by Sunil Glucose Co., Korea are related to processes for increasing physical interacting strength between matrix resin and starch by increasing hydrophobic property of starch or increasing hydrophilic property of matrix resin to increase compatibility with matrix resin and starch.
U.S. Pat. No. 5,281,681A describes photodegradable and biodegradable polyethylene formulation by co-processing ethylene and 2-methylene-1,3-dioxepane (MDOP) to produce terpolymer which exhibits better photodegradability than the copolymer, because the additional carbonyl groups in the polymer cleave upon absorbing light such as sunlight or UV light. The terpolymer can be both photodegradable and biodegradable because both the ester and the carbonyl functionalize.
U.S. Pat. No. 5,461,094A describes biodegradable polyethylene composition chemically bonded with starch and a process for preparing thereof.
Therefore, it is required to provide high yield Peptide-polyethylene herein referred to as PEPlene, having good biodegradability/biocompostability/biodigestion in the environment.